Cell Function

ith its elegant structure and astonishing range of functions, the living cell is an object of wonder. It is the basic unit of all living organisms. There are more than 300 trillion cells in the human body, and every second of every day, more than 10 million die and are re­placed.

In 1665, these impressive structures were named. While examining a thin slice of cork, Robert Hooke (1635-1703), an English scientist and pioneer microscopist, noted that it was made up of tiny boxlike units. The units reminded him of the small enclosures in which monks lived, and he named the microscopic spaces "cells," from the Latin word cells, meaning "small enclosures."

Although Hooke, as well as other scientists, intently studied microscopic life, few guessed the significance of the cells. That would be delayed until microscopes were advanced enough to yield more detailed information. It was with the work of Anton van Leeuwenhoek (1632-1723), a Dutch biologist and microscopist, that the mysteries and importance of the cell were revealed. He ground a single lens to such perfection that he was able to produce a microscope with great resolving power—one that was capable of magnifying a specimen from approximately 50 to 300 times in diameter. Van Leeuwenhoek's work, which included constructing an aquatic microscope that he used to study red blood cells and their flow through the body, was responsible for helping scientists investigate human tissue in ways that once they only dreamed of.